Abstract
From the standpoint of power conservation, the bondgraph represents systems, even those composed of mechanical, hydraulic and electric components, by a unified approach. In this paper, a three ports prsesure regulator valve is represented by the bondgraph, in which hydraulic resisters are nonlinear. The bondgraph of the resisters is constructed with two R-elements consisting of a linear resister and a squared resister. Additionally it is shown that the effect of mixed air is easy to analyse by using two additional C-elements. Dynamic behavior of this valve is obtained easily by the bondgraph simulation in comparison with usual simulation methods.